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1  Using Arduino / LEDs and Multiplexing / Re: Just wanted to share my 32 x 8 LED Matrix on: December 13, 2012, 11:27:47 am
Riva,

so I built just a small quick 8 x 8 with a max7219 using my Uno using the pinout you found....

didn't go so well.....the letters scrolled but were upside down and backwards.....

thats what I hate about these matrices ..they can go in anyway and especially with how the code is written can make them flip all over the place.....Oh well it works good enough for me
2  Using Arduino / LEDs and Multiplexing / Re: Just wanted to share my 32 x 8 LED Matrix on: December 12, 2012, 04:13:40 pm
Thanks for that....Nice find...I'll do some switching around soonish and update the forum...
3  Using Arduino / LEDs and Multiplexing / Re: Just wanted to share my 32 x 8 LED Matrix on: December 12, 2012, 01:18:39 pm
I am making a new layout by manually checking the rows and columns using a power suply to see them illuminate.....

I'l update you soon..I already found  R6 / C6 and  R2 / C2 to be swapped.....
4  Using Arduino / LEDs and Multiplexing / Re: Just wanted to share my 32 x 8 LED Matrix on: December 12, 2012, 01:03:16 pm
Yes, the delay lets it slow down......and I'm beginning to think you're right about the matrices not being wired quite right....I bought them on ebay...they have   XH-1088BRW   on the side of them....

This is what I have for reference but I'll look better for a good datasheet..

The picture is attached....
5  Using Arduino / LEDs and Multiplexing / Re: Just wanted to share my 32 x 8 LED Matrix on: December 12, 2012, 12:42:44 pm
Just uploaded it.....no difference in this compared to the video I posted....
6  Using Arduino / LEDs and Multiplexing / Re: Just wanted to share my 32 x 8 LED Matrix on: December 12, 2012, 12:23:37 pm
Hey Fungus,

You mention a little software tweak can fix the effect......can you check out my code in a thread above and show me maybe where it can fix it please?
7  Using Arduino / LEDs and Multiplexing / Re: Just wanted to share my 32 x 8 LED Matrix on: December 12, 2012, 12:21:27 pm
Ya I noticed the column effect....to me, its good to go..i have worked on this thing forever....One of these days, I want to make the 64 x 8 matrix...easy enough..just cascade more max7219s....just gotta get a large enough PCB
8  Using Arduino / LEDs and Multiplexing / Re: Just wanted to share my 32 x 8 LED Matrix on: December 12, 2012, 09:06:24 am
Oh yes and my arduino Nano.....

code is attached too...

find the max7219 playground schematic and have a good pinout for the matrix before you start connecting them...know the rows and columns...
9  Using Arduino / LEDs and Multiplexing / Just wanted to share my 32 x 8 LED Matrix on: December 12, 2012, 09:04:48 am
so...4 max7219's,  4    8x8 martrices,   4    100 uF caps,  4      0.1 uF caps and 4    27 K ohm resistors later...



10  Using Arduino / LEDs and Multiplexing / Re: How many max7219s can arduino nano 328 control? on: December 07, 2012, 12:06:33 pm
OK !!!  I GOT IT....Iwant to thank Pedro for referring to JoeN...I used his sample code to get my 32 x 8 working..FINALLY!!!!!! 

My code is attached..I'll make a video of it tonight.....
11  Using Arduino / LEDs and Multiplexing / Re: How many max7219s can arduino nano 328 control? on: December 07, 2012, 10:31:40 am
Ok guys, so I have looked over my PCB and probed EVERYTHING!  All grounds are in common along a plane...this would be the arduino GND, The GNDs for all of the Max7219 pins 4 and 9 and all the negative polarity side of any electrolytic caps I use. (As well as the ceramics) but those aren't polarized..so it doesn't matter which side of those caps is grounded.....

All +5 V are present at Pin 19 on all 4  max7219s  and the + 5 is coming from the + 5 Output from the arduino....I have a power supply powering the arduino via it's V in at 8 Volts which is a safe input supply....

I am using 27 K resistors for each of the max7219s which are all sharing the + 5 volt plane....(this is pin 18) 

So the 4 max7219's are daisy chained or (Cascaded)   from the arduino the Clk output is in parallel to all 4 chips and the load output is in parallel to all the chips......Then I have serial data  going from arduino to first max7219  D in  and then cascaded from D out to the next chip's D in....and so on for the rest....

I have ohmed everything and gotten good continuity on all connections....I am using 4   100 u F caps as well as 0.1 u F caps to suprress any noise on each of the chips + 5 / GND  lines.....

I am positive the Rows and columns of the matrices are good...   

I have   four  8 x 8 matrices  making the 32 x 8 display...

  if you think of this:

 [  4th matrix  ]     [  3rd matrix ]    [  2nd matrix  ]     [  1st   matrix  ]        ....laid out like this on the board...


 [4th  max7219]   [3rd  max7219]    [ 2nd max7219]     [1st max7219]     ......laid out right under the matrices.....


  all resistors and caps in place and all V +  and GNDs are good and in common......


the display scrolls from right to left from matrix 1  over to matrix 2  and then leaves 3 and 4 blank.......

I don't get it....

I have attached my schematic I made in EAGLE  and my Code and the pinout I'm using for the max7219...

someone please help....
12  Using Arduino / LEDs and Multiplexing / Re: how to rotate matrix scroll by 90 degrees in code on: December 06, 2012, 06:35:49 pm
Hey crossroads.....how ya been.....so I'm working on a new 32x8, my first one worked ok, all the matrices showed the same letter as it scrolled each one individually ...that was with my mega2560......but now I've got a 16x8 scrolling perfect.....I did just rotate the matrices physically....however I add on two more to make it 32x8 and the 3and 4 matrix are blank while 1and 2 scroll across.....I have them cascaded, all caps and resistors in place.....I'm using a nano this time.......ill paste my code in the morning....
13  Using Arduino / LEDs and Multiplexing / Re: How many max7219s can arduino nano 328 control? on: December 06, 2012, 06:30:57 pm
Well I am using the LedControl library.....but as I said I will paste my code in the morning, maybe someone can look at it and see what I'm not seeing.    But ya all four are cascaded, scrolling from right to left , the furthest matrix right scrolls to the next one left, but then that's it.....the 3rd and 4 th are blank......
14  Using Arduino / LEDs and Multiplexing / How many max7219s can arduino nano 328 control? on: December 06, 2012, 04:36:28 pm
I'm so determined to get this working....I have two 8x8 one color matrices scrolling beautifully...making the 16x8 display.....each controlled by its own max7219 , caps are placed for  each and They are cascaded ( Dout to Din) so anyways, I hooked up two more matrices making the 32x8 display....cascaded them as well. Caps for each chip there too....so recap, 4 chips, 4 matrices, the Rset resistor and 8 caps ( 2 for each chip) but only two of the four matrices are scrolling....the other two are blank....there was signs the chips turn on due to the matrices initially totally lighting up, but when it scrolls from right to left, it goes from matrix 1 to 2 but nothing when its 3's turn.....I will paste my code tomorrow as I just left work....the loads are in parallel for each, the clocks are as well.
15  Using Arduino / LEDs and Multiplexing / Re: how to rotate matrix scroll by 90 degrees in code on: December 05, 2012, 03:21:43 pm
I'm sorry I don't follow.....how would you rewrite it
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